This project is designed to develop finite element models for integration with experimental investigations in order to provide analysis of the optimum methods of achieving electrical defibrillation. The project requires massively parallel computers to provide the computational power required for detailed models. The voltage gradients in the model will be correlated with those measured in mongrel dogs using a bipolar technique in order to assess the quality of the mathematical model. A human finite element model will also be developed to aid in direct analysis and optimization of the defibrillation process in humans. Thus, the project will establish specific guidelines for the construction of accurate finite element models and help to identity optimal defibrillation conditions and device design guidelines.